By Melissa Zhu

Remember Joe Johnston’s iconic 1989 film, Honey, I Shrunk the Kids?

In that movie, an eccentric inventor accidentally shrinks his and his neighbours’ kids with a ray gun.

The plot might’ve been hilarious in part due to its absurdity, but the actual technology which creates such miniature worlds invisible to the naked eye isn’t all that far off. Breakthrough research in nanoplasmonics by a team from A*STAR’s Institute of Materials Research and Engineering (IMRE), the National University of Singapore (NUS) and the Singapore University of Technology and Design (SUTD) is proof of this.

Wait. Nano…what?

Nanoplasmonics is a field of study focusing on how light behaves around tiny metal particles (at a scale of a billionth of a metre). For instance, miniscule silver and gold particles suspended in stained glass are the reason why we see yellow and red tones when light passes through it.

Research in the field has allowed one of the scientists in the team, Dr Shawn Tan, to “shrink” his wife’s favourite painting, Claude Monet’s Impression, Sunrise right down to the width of three human hairs. And if she so wished, she could carry it around embedded in a piece of jewellery, or in her wallet.

(This scientist sure knows how to score brownie points!)


Monet’s “Impression, Sunrise” (left), and the A*STAR team’s microscopic replica

The technique developed by Dr Tan’s team uses aluminium nanostructures, instead of traditional ink pigments, for colour printing. When varied in size, shape and relative positioning, the aluminium particles tune and focus light differently, hence “creating” different colours that are seen by the human eye.

This discovery, which is the world’s first plasmonic colour system for aluminium, is revolutionary in several ways.

For one, the technique has achieved the highest resolution for colour prints in the world, reaching 100,000 dpi. That means that it could reproduce prints with the quality of glossy magazines at a size 300 times smaller. In fact, the team’s Monet replica has made history as the smallest ever reproduction of a painting in full colour.

With numerous variations of size and spacing between aluminium nanostructures, nanoplasmonic printing can also increase the range of printable colours. Currently, the researchers can print more than 300 colours using nanoplasmonics.

“We wanted a challenge to test the type of colours that we could get, and with Monet’s “Impression, Sunrise”, we found that challenge in its very subtle brushstrokes and variations in colour.”

- Dr Tan, Scientist at the Institute of Materials Research and Engineering (IMRE), A*STAR

Nanoplasmonic printing is capable of producing over 300 colours, expressing extremely subtle variations within a tiny space.

In addition, nanoplasmonic printing circumvents problems associated with conventional dyes and chemicals. Most notably, the fading of dyes due to chemical reactions, the need for different dyes for different colours, and the effect of dye-related chemical waste on the environment. The aluminium structures naturally form an impermeable native oxide layer, creating a protective coating that preserves the colours.

Dr Tan, one of 10 innovators who made it to Emtech Singapore’s Innovators Under 35 list recently, said that this new technology will open up many more opportunities for colour printing. Possible applications include personalised jewellery, branding and authentication for high value goods, as well as a variety of security uses, such as currency authentication or access cards that are practically impossible to duplicate.

Now, imagine proposing with a ring inscribed with the tiniest love letter in the world – the wedding industry would never be the same again.

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